I bought a new home last year and I have had to some work correcting some negative grading around the house. The settling that occured over the years before I bought the house has also sunk the concrete pad that my central AC condenser sits on pretty low. I have bricks stuck under it for now and this weekend's big rains had water right up under the unit - it would have been under water if not for the bricks.

So, in order to correct the grad on that corner of the house, I will need to first correct the pad as it would be buried otherwise. As far as I can see, my basic options are:

break out the old pad and have a new one poured.

try to lift the old pad and gradually build up some gravel/fill underneath it to bring it up to where it should be.

Now, I'm not sure if I shoudl be asking this in another forum, but could I either pour a new pad right over the existing one without breaking it out first?
Also, does anyone have experience with using a plastic pad? I would probably just leave the old concrete pad in place if I went with one of these.

Thanks for any info or advice!

SD515

09-14-2008 10:28 PM

Many condensers I've installed or worked on have plastic pads. Quick & easy, inexpensive. The key is a solid base under it. If you believe the original concrete pad is in good shape and has finally stopped settling or at least has slowed way way down, and it's fairly level, slip a plastic pad under it if it'll fit. You could even creatively fasten 2 pads together (bolts, screws, etc.) if need be. If the height you need to achieve is too great, it will put stress on the copper lines, so there's a limit you can raise it before you have to have the lines disconnected and reset. I would not suggest trying to bend the pipes if you haven't any experience with AC lines...they are 'delicate' in that they kink very easily.

biggles

09-14-2008 10:40 PM

if you have some play on the refer lines that go from the condenser to where they enter the house on the horizontal try this.disconnect the electric on the service shut off for the condenser and walk the condenser out from the exsisting location to just clear the area 100% for the regrade.you can built a temporary base out of some scrap 2x4s and cinder blocks/bricks just to keep it stable.they plastic pads are engineered to do the job and are very popular with installs.your local www.grainger.com has pads and welcome DIYrs over the counter.to move the condenser without lifting if your going for the swing out is a long piece of cardbaord or old plywood and place it in the direction of the move,and put a piece of scrap carpet with the fabric down on the wood.place the condenser on it and slide the carpet on the wood/cardboard out of the way